Double screen structure



Feb 9, 194f3 o. c. GRUENDER DOUBLE SCREEN -STRUCTURE 4 Sheets-Sheet lfigg/MM Original Filed June 11.11958 Feb. 9, 1943. .0, GRUENDER2,310,736

DOUBLE SCREEN STRUCTURE Original Filed June 11, 1938 4 Sheets-Sheet 2Feb., 9, 1943. o. c. GRUENDER 2,310,736

DOUBLE SCREEN STRUCTURE l original Filed June 11, lsa 4 sheets-she@ sWzy fie' 'We/?? 05cm" @rae/wier Fel 9, 1943- o. c. GRuENnl-:R

*DOUBLE SCREEN STRUCTURE original Filed June 11, 1938 4 sheets-sheet 4fiyef? Zoy @Jaar @maeva/62 Patented Feb. 9, 1943 2,310,736 DOUBLE SCREENSTRUCTURE scar C. Gruender, Milwaukee, Wis., assigner to NordbergManufacturing Co., Milwaukee, Wis., a corporation of Wisconsin Originalapplication June 11, 1938, Serial No. 213,193. Divided and thisapplication July 15, y 1940, Serial No. 345,598

8 Claims. (Cl. 209-240) My invention relates to improvements in screensand has for one purpose the provision of a screen which shall be simpleto manufacture,I

compact, and efficient in use.

Another purpose is the provision of improved means for providing ascreen of substantial length in which a plurality of separate units areemployed.

Another purpose is the provision of an improved screen frame or deck.

Another purpose is the provision of an improved screen in which aplurality of sections feed the material under the screen in oppositedirections, and preferably in such fashion as to cause the dischargefrom a plurality of sections to join at a unitary discharge area. y

The present application is a division oi my copending application SerialNo. 213,193, led in the United States Patent Oiilce on June l1, 1938.

Other purposes will appear from time to time in the course of thespecification and claims.

I illustrate my invention more or less diagrammatically in theaccompanying drawings, wherein:

Figure 1 is a side elevation; l

Figure 2 is a section on the line 2-2 of Figure 1, on an enlarged scale,with parts omitted;

Figure 3 is a section on the line 3-3 of Figure l, on an enlarged scale;

Figure 4 is a section-on the line 4-4 of Figure 1, on an enlarged scale;

Figure 5 is a section on the line 5-5 of Figure 4; and

Figure 6 is a section on the line 6-6 of Figure 4.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings, I generally indicates a normally xed screenframe which may include horizontal top frame members or channels 2,horizontal bottom frame members or channels 3, vertical end framemembers 4, 5, inclined braces 1, and screen frame members or channels 8,and intermediate transverse members, channels or angles 9. I0, indicateany suitable hopper members having downspouts or discharge members i2,I3.

Intermediate the hoppers i0 and are any suitable .discharge chutes |20,2|, the upper chute |20 being adapted to receive the discharge from theupper level of the two screen decks below described, and the chute |2|being adapted to receive the discharge from the lower level of the twosaid screen decks, as generally indicated at A and B in Figure 1.

In order to deliver material to the screen assembly, I may provide anysuitable intermediate feeding means, forv example the member |22, whichmay be a chute or a belt, discharging to feed chutes |23, |24,`which inturn discharge to initial feed spouts I8 and |8a, located at theopposite ends of the frame member I, which deliver to the screen unitsor decks A and B, respectively.

It will be understood that the member or conveyor |22 extends generallyat right angles to the path of movement of the screens, and it will vbeobserved that the conveyors |20 and |2I lie in a vertical plane commonalso to the conveyor |22, and extending generally at right angles to thepath of movement of the'screens.

Referring to Figure 1, I provide the screen decks A and B, each of whichmay include side plates 25. Extending longitudinally along the sides areinner channels 26, 21, which may be welded or otherwise secured to theside plates 25, and at the upper iiange of each channel is positioned asmaller channel 28, in which is carried a padl 29 of rubber or suitableyielding and compressiblematerial, herein shown as filling the spacebetween the anges of the channel 28 and extending upwardly above theupper edges of said anges. Transverse frame members 30, 3| are employedextending between side plates 25 and channels 26, 21.

As shown in detail in Figure 6, taken in connection with Figure 4, Iillustrate upstanding angles 32, 33 placed back to back on the members30 or 3| and extending between them a longitudinal member 34, upon thetop of which is mounted an upwardly open channel 35 having therein a pad36 of yielding compressible material similar to the side pads 29 andrunning lengthwise of the screen. Two or more may be employed. Thescreen cloth may be laid over the pads 36 and is preferably formed withan inwardly turned hook-like edge portion 38 which overlies the sidepads 29.

39 indicates a lever plate, the toe of which -as at 40 abuts against asmall angle iron 4| secured to the upper inner face of the side plate25. The lower toe 42 sets within the recurved portion 38 of thescreenedge. An intermediate portion 43 is apertured to receive the bolt44 with its outer nut 45. 46 is a coil spring compressed between the nutor its washer 41 and the outer face of the plate 25, whereby the member44 with its head 48 draws the member 39 inwardly and somewhat downwardlyand compresses the edge portion 38 of the screen cloth against the uppersurface of the pacl 29. The result is a stretching and a very firm holdon the screen cloth. The lower screen assembly is the same as abovedescribed, except that the toe 40 abuts against the lower flange of thechannel iron 21. It will be observed that the mesh is at all timesmounted upon and resting upon pads of yielding compressible material,and is not at any point gripped between opposed metallic surfaces. Thecompression may be readily adjusted by rotation of the nut 45. Thescreen may readily be removed by slacking the nuts 45 and removing thebolts 44.

The structure of the two screens A and B is substantially the same andneed not be separately described. Each section is mounted upon aplurality of compound leaf springs generally indicated at 50 inFigure 1. Each one of the spring members may be formed of a plurality ofparallel leaves mounted at their upper ends in brackets on the inside ofthe upper channels 2. Similar brackets 52 are secured to the lower endsof the spring units and to the outer faces of the side plates 25. Thuseach one of the spring units A and B is floated on a plurality of leafsprings inclined somewhat from the perpendicular.

I prefer to have the screens feed in opposite directions. For example,the deck A receives its material from the feed spout I8, and the deck Bfrom the feed spout |8a at the opposite ends of the frame. The oversizefrom the two decks is delivered to the chutes |20 and |2|, and whatpasses through the mesh of the decks is received by the hoppers I0 andFor convenience, I will indicate the upper screen cloth of section A asX and the upper screen cloth of section B as X-|. I will indicate thelower screen cloth of section A as Y and the lower screen cloth ofsection B as Y-l.

|9 indicates any suitable motor or power source, herein shown as mountedon the screen` frame itself, upon transversely extending angles 20. Themotor pulley 2|, through a belt 22, drives a vibrating unit on one ofthe screen sections.

Referring to the vibrating unit, which in the form of Figure 1 is shownmounted on screen section A, its details will be shown for example inFigures 1, 2 and 3. I illustrate for example reinforcing plates 60 whichmay be welded or otherwise secured to the side plates 25. Mounted in anaperture in the reinforcing plates 60 is a bearing housing whichincludes a member 62 having a flange 62a and a generally cylindricalwall member 63 having a flange 63a. Bolts 63h and nuts 63c secure theflanges 62a and 63a to the side plate 25 and the reinforcing plate 60.Secured to the member 63 by means of the bolts 64a is an inner member 64having a generally cylindrical flange 65 in which is mounted acylindrical housing and strut member 66. 61 is an outer-,ball or rollerrace and B8 an inner race, 69 indicating the rollers.

Mounted for rotation with the inner race 68 is a shaft portion 10 havingan inner extension 1| which is cut away as at 12 to provide a balancefor the outer eccentric structure below described. 13 is an outer memberrotating with the shaft and including a labyrinth connection generallyindicated as 14 with the member 62, whereby the escape of oil and theentry of dust is prevented. 15 is an eccentric shaft extension from theshaft 10 to the end of which is secured any suitable pulley 16 aboutwhich passes the belt 22 where-V by the eccentric structure may berotated from the motor I9. 11 is an inner roller race mounted on theshaft 15 and surrounded by an outer race 18 with rollers 19therebetween. Surrounding and associated with the outer race is aknuckle joint 00 of a connecting rod 8| which extends to the oppositescreen. The knuckle has labyrinth connections 83 with the pulley 16, and6l with the member 13, whereby the roller bearings are protected.

At the opposite end of the connecting rod 8| is a split hub 85 which maybe compressed as by the bolt 86 and nut 81. It surrounds a connectingstructure mounted on the screen unit B which includes an outer sleeve88, an inner sleeve 89, and an interposed sleeve of rubber or the likewhich may be vulcanized to the members 88 and 89, whereby the interiordeformation of the compressible and yielding member 90 compensates forthe slight oscillatory rotation of the member 85 and prevents any metalto metal bearing contact. Positioned within the inner sleeve 89 is atrunnion 9| which may be formed unitarily with a casting 92 having apositioning stud 93 extending inwardly through the side plate 25 and thereinforcing member 60. It may further be held in position as by anysuitable bolts 94 and nuts 95. The same nuts and bolts may extendthrough the outer flange 96 of an inner plate 91, having a cylindricalflange 98 in which is positioned a tubular strut 99. The member 91 hasan aperture as at |00 which also receives the inner end of the member93. Thus a firm vibrating contact is provided for the screen unit.

The trunnion 9| has a reduced threaded end 9|a to receive a washer 9|band a nut 9|c to secure the sleeve 89 in position. In order tocounterbalance the difference in weight of the vibrating unit on screenunit B and the connecting structure on screen unit A, I may provideweights on either or both screen units, as at ||0 on unit A and on unitB as shown in Figure 1.

Where the tubular members or struts 66 or 99 extend across the screensections, it will be understood that any suitable means may be employed,such as the welded plates |0| for carrying the members 34 thereacross.Since the strut unit is removable, I flnd it preferable to provide aremovable connection between the members 34 and the plates |0I, whichmay include the bolts |02 and nuts |03. The lever plates 39 are cut downas at 39a to pass under the members 63 and 91.

It will be realized that my description and drawings are in a broadsense illustrative and diagrammatic and that many changes in size,shape, number and disposition of parts may be made. I therefore do notwish to be limited specifically to the devices herein shown except tothe extent that I may possibly limit myself in the claims.

It will be understood that, whereas I have shown but a single link 8| atone side of the screen, the link structure may be duplicated on eachside of the screen.- In the drawings only one-half of the screen isshown.

This type of screen lends itself to a compact installation in whichthere is a minimum of lateral length permitted. For instance, I mayemploy a single main feed spout or conveyor |22, which by branch chutes|23 and |24 may deliver material to be screened to the feed chutes orspouts I8 and |8a. A minimum of longitudinal outward extension of thescreen structure is needed and all of the screen material can escapefrom the screen unit intermediate its length, either through the spoutsI20, I2I, or through the spouts I2, I3. 'I'he use and operation of myinvention are as follows:

The material is fed by any suitable conveying means, such, for example,as the chutes |22 and I23, to the end delivery spouts I8 and Ila. Thusthe material to be screened is delivered to the top mesh X and X-I ofthe two decks A and B, and moves inwardly toward the adjacent ends ofthe two decks. The fines sift through the mesh X and X-I and arereceived on the lower level mesh Y and YI. Here in turn the fines escapethrough the mesh as the decks A and B are vibrated, and are received inhoppers III and II, and passout through the spouts I2 and I3. Theoversize from the upper mesh X, X-I is received by the upper trough |20,and the oversize from the lower mesh Y, Y-I is received by the lowercentral trough or chute I2I.

The inclination of the springs 50 in opposite direction keeps the screenframes A and B in balance. The two decks, in a broad sense, act as aunit, and I therefore obtain the advantage of a long screen, with agreat economy of construction and operation. A single vibratory unit ofone screen section is perfectly adequate to vibrate both sections, andthe vibrating transmitting mechanism I have shown, including theconnecting rod BI, emciently applies a substantially uniform vibrationto the two screen sections, which vibration, however, is in oppositedirections.

The unbalanced member is enclosed and, shielded by the transversetubular strut 68. It will be observed in Figure 2 that the center ofrotation a of the shaft 10, 1I in relation to the screen section iseccentric in relation to the center of rotation b of the pulley 16. Theaxis c of the eccentric shaft extension and of the con necting rodconnection 80, however, is eccentric to both. In practice, the rotationof the unit thus described results in a vibration having a throwsubstantially twice the distance separating the center of rotation a ofthe shaft 10 in relation to the screen section, and the center ofrotation c of the eccentric shaft extension 15.

I claim:

l. In a vibrating screen structure, a base, a plurality of screenelements and means for supporting them vibratably upon said base, saidscreen elements being located end to end, and means for simultaneouslyvibrating said screen elements including a shaft mounted on one of saidelements and extending transversely thereacross in a generallyhorizontal plane, means for mounting said shaft rotatably upon saidscreen element, including bearing means eccentric `to the shaft, meansfor rotating the shaft including a pulley mounted on the shaft, the

axis of the pulley being eccentric to the shaft and to the bearingconnections between the shaft and the screen element and being locatedsubstantially midway between them, anda link including an eyesurrounding an outwardly extending portion of the shaft, and aconnection between said link and the other screen element, said shaftand said connection between the link and other screen element beinglocated upon adjacent ends of the two screen elements, and means forsupporting said screen elements, including leaf springs secured each atone end to the base and at the other to one of said elements, saidsprings being inclined substantially from the perpendicular, the springsfor each element being generally parallel, the springs for the twoelements being inclined in opposite directions from the perpendicular,and at substantially the same angle.

2. In a vibrating screen structure. a base. a plurality oi' screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, each suchelement having generally horizontal mesh, meansfor impartingsimultaneously to said elements a screening and conveying vibration,including a link pivoted at one end to one of said screen elements andhaving an eye at the opposite end and an eccentric on the oppositescreen element penetrating said eye. and means for rotating it and forthereby varying the distance between said screen elements, unitary meansfor feeding material simultaneously from a single source to the feedends of said screen elements, and unitary means located between theopposed ends of the screen elements for receiving simultaneously thedischarge from said screen elements.

3. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other,.each suchelement having generally horizontal mesh, means for impartingsimultaneously to said elements a screening and conveying vibration,including a link pivoted at one end to one of 'said screen elements andhaving an eye at the opposite end and an eccentric on the oppositescreen element penetrating said eye, and means for rotating it and forthereby varying the distance between said screen elements, unitary meansfor feeding material simultaneously from a single source to the feedends of said screen elements, and unitary means located between theopposed ends of the screen elements for receiving simultaneously thedischarge from said screen elements, and means for supporting saidscreen elements, including a plurality of leaf springs extending fromsaid base to said screen elements.

4. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, each suchelement having generally horizontal mesh, means for impartingsimultaneously to said elements a screening and conveying vibration,including a link pivoted `at one end to one of said screen elements andhaving an eye at the opposte end and an eccentric on the opposite screenelement penetrating said eye, and means for rotating it and for therebyvarying the distance between said screen elements, unitary means forfeeding material simultaneously from a single source to athe feed endsof said screen elements, and unitary means located between the opposedends of the screen elements for receiving simultaneously the dischargefrom said screen elements, and means for supporting said screenelements, including a plurality of leaf springs extending from said baseto said screen elements, said leaf springs being inclined substantiallyfrom the vertical, the springs of each said screen element beingoppositely inclined.

5. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, unitary meansf or imparting simultaneously to said elements a screening and conveyingvibration, unitary means for feeding material simultaneously from asingle source to the feed ends of said screen elements, means locatedbetween the opposed ends 'of the screen elements for receivingsimultaneously the discharge from said screen elements, the means forimparting simultaneous vibration to the screen elements, including arotary member mounted on one oi said elements, and means for rotatingit, and an actuating connection between said rotary member and the otherof said elements.

6. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, unitary meansfor imparting simultaneously to said elements a screening and conveyingvibration, unitary means for feeding material simultaneously from asingle source to the feed ends of said screen elements. means locatedbetween the opposed ends of the screen elements for receivingsimultaneously the discharge from said screen elements, including aplurality of superposed conveyors extending in a direction generally atright angles to the path of movement of the material across the screenelements and lying in a common vertical plane, and located between thescreen elements, the means for imparting simultaneous vibration to thescreen elements including a rotary member mounted on one of saidelements, and means for rotating it, and an actuating connection betweensaid rotary member and the other of said elements.

'7. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, unitary meansfor imparting simultaneously to said elements a screening and conveyingvibration, unitary means for feeding material simultaneously from asingle source to the feed ends of said screen elements, and meanslocated between the opposed ends of the screen A elements for receivingsimultaneously the discharge from said screen elements, including aplurality of superposed conveyors extending in a direction generally atright angles to the path of movement of the material across the screenelements and lying in a common vertical plane, and located between thescreen elements.

8. In a vibrating screen structure, a base, a plurality of screenelements independently mounted upon said base and located generally endto end, with their discharge ends opposite to each other, unitary meansfor imparting simultaneously to said elements a screening and conveyingvibration, unitary means for feeding material simultaneously from asingle source to the feed ends of said screen elements, including a mainfeed conveyor extending along a path generally at right angles to thepath of movement of the screens, and sub-conveyors extending laterallyin opposite directions from said conveyor to the feed end of eachscreen, said main feed conveyor being located generally vertically abovethe discharge ends of the screens, means located between the opposedends oi.' the screen elements for receiving simultaneously the dischargefrom said screen elements, including a plurality of superposed conveyorsextending in a direction generally at right angles to the path ofmovement of the material across the screen elements, and located betweenthe screen elements, and lying in the same general vertical plane as themain feed conveyor, the means for imparting simultaneous vibration tothe screen elements including a rotary member mounted on one of saidelements, and means for rotating it, and an actuating connection betweensaid rotary member and the other of said elements.

OSCAR C. GRUENDER.

